Unidentified Sesquiterpene Research Articles

Artemdubinoids A–N: novel sesquiterpenoids with antihepatoma cytotoxicity from Artemisia dubia

In pursuit of effective agents for hepatocellular carcinoma derived from the Artemisia species, this study built upon initial findings that an ethanol (EtOH) extract and ethyl acetate (EtOAc) fraction of the aerial parts of Artemisia dubia Wall. ex Bess. exhibited cytotoxicity against HepG2 cells with inhibitory rates of 57.1% and 84.2% (100 μg·mL−1), respectively. Guided by bioactivity, fourteen previously unidentified sesquiterpenes, artemdubinoids A–N (1–14), were isolated from the EtOAc fraction. Their structural elucidation was achieved through comprehensive spectroscopic analyses and corroborated by the comparison between the experimental and calculated ECD spectra. Single crystal X-ray diffraction provided definitive structure confirmation for artemdubinoids A, D, F, and H. Artemdubinoids A and B (1–2) represented unique sesquiterpenes featuring a 6/5-fused bicyclic carbon scaffold, and their putative biosynthetic pathways were discussed; artemdubinoid C (3) was a novel guaianolide derivative that might be formed by the [4 + 2] Diels–Alder reaction; artemdubinoids D and E (4–5) were rare 1,10-seco-guaianolides; artemdubinoids F–K (6–11) were chlorine-containing guaianolides. Eleven compounds exhibited cytotoxicity against three human hepatoma cell lines (HepG2, Huh7, and SK-Hep-1) with half-maximal inhibitory concentration (IC50) values spanning 7.5−82.5 μmol·L−1. Artemdubinoid M (13) exhibited the most active cytotoxicity with IC50 values of 14.5, 7.5 and 8.9 μmol·L−1 against the HepG2, Huh7, and SK-Hep-1 cell lines, respectively, which were equivalent to the positive control, sorafenib.

Undetected biogenic volatile organic compounds from Norway spruce drive total ozone reactivity measurements

Abstract. Biogenic volatile organic compounds (BVOCs) are continuously emitted from terrestrial vegetation into the atmosphere and react with various atmospheric oxidants, with ozone being an important one. The reaction between BVOCs and ozone can lead to low volatile organic compounds, other pollutants, and the formation of secondary organic aerosols. To understand the chemical and physical processes taking place in the atmosphere, a complete picture of the BVOCs emitted is necessary. However, the large pool of BVOCs present makes it difficult to detect every compound. The total ozone reactivity method can help understand the ozone reactive potential of all BVOCs emitted into the atmosphere and also help determine whether current analytical techniques can measure the total BVOC budget. In this study, we measured the total ozone reactivity of emissions (TOZRE) from a Norway spruce tree in Hyytiälä in late summer using the total ozone reactivity monitor (TORM) built at the Finnish Meteorological Institute (FMI). Additionally, we conducted comprehensive chemical characterisation and quantification of BVOC emissions using a gas chromatograph coupled with a mass spectrometer (GC–MS), enabling us to estimate the calculated reactivity of emissions (COZRE). TOZRE reached up to 7.4×10-9 m3 s−2 g−1, which corresponds to 65 µg g−1 h−1 of α-pinene. Stress-related sesquiterpenes, such as β-farnesene and α-farnesene, and an unidentified sesquiterpene contributed the most to the observed emissions. However, COZRE made up only 35 % of the TOZRE, with sesquiterpenes being the most important sink for ozone. High TOZRE values were especially seen during high-temperature periods, with up to 95 % of TOZRE remaining unexplained. Emissions of unidentified stress-related compounds could be the reason for the high fraction of missing reactivity.

Identification and characterization of novel sesquiterpene synthases TPS9 and TPS12 from Aquilaria sinensis.

Sesquiterpenes are characteristic components and important quality criterions for agarwood. Although sesquiterpenes are well-known to be biosynthesized by sesquiterpene synthases (TPSs), to date, only a few TPS genes involved in agarwood formation have been reported. Here, two new TPS genes, namely, TPS9 and TPS12, were isolated from Aquilaria sinensis (Lour.) Gilg, and their functions were examined in Escherichia coli BL21(DE3), with farnesyl pyrophosphate (FPP) and geranyl pyrophosphate (GPP) as the substrate of the corresponding enzyme activities. They were both identified as a multiproduct enzymes. After incubation with FPP, TPS9 liberated β-farnesene and cis-sesquisabinene hydrate as main products, with cedrol and another unidentified sesquiterpene as minor products. TPS12 catalyzes the formation of β-farnesene, nerolidol, γ-eudesmol, and hinesol. After incubation with GPP, TPS9 generated citronellol and geraniol as main products, with seven minor products. TPS12 converted GPP into four monoterpenes, with citral as the main product, and three minor products. Both TPS9 and TPS12 showed much higher expression in the two major tissues emitting floral volatiles: flowers and agarwood. Further, RT-PCR analysis showed TPS9 and TPS12 are typical genes mainly expressed during later stages of stress response, which is better known than that of chromone derivatives. This study will advance our understanding of agarwood formation and provide a solid theoretical foundation for clarifying its mechanism in A. sinensis.

Why shading cedar (Cedrela fissilis) reduces damage caused by mahogany shoot borer, Hypsipyla grandella (Zeller)?

Cedar (Cedrela fissilis) is a major timber species native to South America that has suffered frequent impacts from illegal harvesting. Cultivation efforts have experienced recurrent failures due to the action of the mahogany shoot borer Hypsipyla grandella, which, when attacking the plants in the first years of growth, inflicts negative effects on the commercial use of this timber. One of the methods used to reduce attacks by this insect is planting cedar in shaded areas, but the factor that makes shaded plants to be less attacked is still unknown. Considering that variation in photosynthetically active radiation can alter the emission of volatile organic compounds (VOCs) from plants, our hypothesis is that shading cedar plants alters their production of volatile compounds, including those that affect host location by H. grandella adults. To check this hypothesis, the authors used an air-entrainment system to collect VOCs emitted by cedar under different levels of artificial shading (50%, 30%, 15%) and full sunlight. The influence of the volatiles emitted by cedar plants on H. grandella was then assessed through electroantennographic/GC assays. One volatile compound, methyl salicylate, which was found to experience enhanced emission in shaded cedar plants, was then subjected to a field experiment to evaluate its influence on host location by H. grandella moths. From thirty VOCs emitted by the tested cedar plants, nine exhibited enhanced emission when plants were shaded: methyl salicylate, methyl-5-methylhexanoate, the monoterpenes α-pinene and eucalyptol, the homoterpenes (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E-E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT) the sesquiterpenes, β-caryophyllene, β-cubebene and an unidentified sesquiterpene. Antennal response from H. grandella female and male antennae was observed to four volatile compounds, nonanal, decanal, methyl salicylate, and β-caryophyllene, when stimulated with the air-entrainment cedar plant extracts. A synthetic blend comprising these four compounds also elicited antennal responses from H. grandella. Field studies showed that plants treated with methyl salicylate exhibited a lower rate of damage by H. grandella caterpillars. These results indicate the potential of this semiochemical as a management tool for H. grandella in cedar cultivations.

Sesquiterpene biosynthesis in a leafy liverwort Radula lindenbergiana Gottsche ex C. Hartm

Liverworts (Marchantiophyta) are among the earliest diverging lineages of extant land plants. Among their unique features, most liverworts contain membrane-bound oil bodies, organelles that accumulate diverse secondary metabolites, especially terpenoids. In contrast to the rich information on liverwort terpenoid chemistry, little is known about their biosynthesis. Recently, terpenoid biosynthesis was studied in a model thalloid species Marchantiapolymorpha, in which sesquiterpenes and monoterpenes are biosynthesized by a new type of terpene synthases termed microbial terpene synthase-like (MTPSL) proteins. Here we study terpenoid biosynthesis in a leafy liverwort Radula lindenbergiana. Vegetative plants of R.lindenbergiana were found to contain a mixture of sesquiterpenes, with (E,E)-α-farnesene/β-curcumene and (Z)-β-bisabolene being the most abundant constituents. From the analysis of the R. lindenbergiana transcriptome, five full-length MTPSL genes were identified. They were designated RlMTPSL1-5, respectively. Recombinant RlMTPSL proteins were produced in Escherichia coli and tested for sesquiterpene synthase activities using farnesyl diphosphate (FPP) as substrate. All except RlMTPSL5 were demonstrated to catalyze the formation of different sesquiterpenes. RlMTPSL1 produced multiple sesquiterpenes with eremophilene and an unidentified sesquiterpene as major products. The major products of RlMTPSL2 and RlMTPSL3 were β-elemene and an unidentified sesquiterpene, respectively. RlMTPSL4 was also a multi-product sesquiterpene synthase with an unidentified sesquiterpene being the major product. Homology-based structural modeling was performed to understand the structural basis underlying different product profiles of the RlMTPSLs proteins. Most of the sesquiterpene products of the four active RlMTPSLs were also detected in R. lindenbergiana plants. Expression levels of the four RlMTPSL genes encoding active enzymes in vegetative plants were compared. In phylogenetic analysis, RlMTPSL genes were found to cluster together, indicating lineage-specific expansion of MTPSL genes in lineages leading to R.lindenbergiana and M. polymorpha. This study strengthens evidence for the contribution of MTPSL genes to terpenoid biosynthesis in liverworts.

Sesquiterpenes and oxygenated sesquiterpenes dominate the VOC (C<sub>5</sub>–C<sub>20</sub>) emissions of downy birches

Abstract. Biogenic volatile organic compounds (BVOCs) emitted by the forests are known to have strong impacts in the atmosphere. However, lots of missing reactivity is found, especially in the forest air. Therefore better characterization of sources and identification/quantification of unknown reactive compounds is needed. While isoprene and monoterpene (MT) emissions of boreal needle trees have been studied quite intensively, there is much less knowledge on the emissions of boreal deciduous trees and emissions of larger terpenes and oxygenated volatile organic compounds (OVOCs). Here we quantified the downy birch (Betula pubescens) leaf emissions of terpenes, oxygenated terpenes and green leaf volatiles (GLVs) at the SMEAR II boreal forest site using in situ gas chromatographs with mass spectrometers. Sesquiterpenes (SQTs) and oxygenated sesquiterpenes (OSQTs) were the main emitted compounds. Mean emission rates of SQTs and OSQTs were significantly higher in the early growing season (510 and 650 ng gdw-1 h−1, respectively) compared to in the main (40 and 130 ng gdw-1 h−1, respectively) and late (14 and 46 ng gdw-1 h−1, respectively) periods, indicating that early leaf growth is a strong source of these compounds. The emissions had a very clear diurnal variation with afternoon maxima being on average 4 to 8 times higher than seasonal means for SQTs and OSQTs, respectively. β-Caryophyllene and β-farnesene were the main SQTs emitted. The main emitted OSQTs were tentatively identified as 14-hydroxy-β-caryophyllene acetate (M=262 g mol−1) and 6-hydroxy-β-caryophyllene (M=220 g mol−1). Over the whole growing season, the total MT emissions were only 24 % and 17 % of the total SQT and OSQT emissions, respectively. A stressed tree growing in a pot was also studied, and high emissions of α-farnesene and an unidentified SQT were detected together with high emissions of GLVs. Due to the relatively low volatility and the high reactivity of SQTs and OSQTs, downy birch emissions are expected to have strong impacts on atmospheric chemistry, especially on secondary organic aerosol (SOA) production.

The Sesquiterpene Synthase PtTPS5 Produces (1S,5S,7R,10R)-Guaia-4(15)-en-11-ol and (1S,7R,10R)-Guaia-4-en-11-ol in Oomycete-Infected Poplar Roots.

Pathogen infection often leads to the enhanced formation of specialized plant metabolites that act as defensive barriers against microbial attackers. In this study, we investigated the formation of potential defense compounds in roots of the Western balsam poplar (Populus trichocarpa) upon infection with the generalist root pathogen Phytophthora cactorum (Oomycetes). P. cactorum infection led to an induced accumulation of terpenes, aromatic compounds, and fatty acids in poplar roots. Transcriptome analysis of uninfected and P. cactorum-infected roots revealed a terpene synthase gene PtTPS5 that was significantly induced upon pathogen infection. PtTPS5 had been previously reported as a sesquiterpene synthase producing two unidentified sesquiterpene alcohols as major products and hedycaryol as a minor product. Using heterologous expression in Escherichia coli, enzyme assays with deuterium-labeled substrates, and NMR analysis of reaction products, we could identify the major PtTPS5 products as (1S,5S,7R,10R)-guaia-4(15)-en-11-ol and (1S,7R,10R)-guaia-4-en-11-ol, with the former being a novel compound. The transcript accumulation of PtTPS5 in uninfected and P. cactorum-infected poplar roots matched the accumulation of (1S,5S,7R,10R)-guaia-4(15)-en-11-ol, (1S,7R,10R)-guaia-4-en-11-ol, and hedycaryol in this tissue, suggesting that PtTPS5 likely contributes to the pathogen-induced formation of these compounds in planta.

The ethnobotany and major essential oil compounds of anise root (Annesorhiza species, Apiaceae)

A comprehensive review of indigenous knowledge about a traditional Cape, San and Khoi food item called anise root or anyswortel (genus Annesorhiza) is presented. The first accurate record was by Thunberg in 1772 at the Berg River near Vlermuisdrift (now Bridgetown) in the Western Cape and applied to A. grandiflora. Four species have recorded food uses as root vegetables (A. grandiflora, A. macrocarpa, A. nuda and an as yet undescribed species from Namaqualand) and two species (A. nuda and A. flagellifolia) as leaf vegetables. Essential oils of this genus were studied for the first time. Hydro-distilled oil from the fleshy roots, leaves and fruits of three species recorded as edible (A. grandiflora, A. macrocarpa and A. nuda) were chemically characterized using GC–MS and NMR spectroscopy. Noteworthy differences were found between plant parts as well as species. Estragole and a small amount of anethole occur in the roots of A. nuda (but not in any of the other two species). The major components of A. grandiflora fruits were dillapiole, nothoapiole and limonene, while elemicin was identified in the roots of the same species. Fruits of A. macrocarpa contained methyleugenol, the leaves ethyl-benzenes and α-terpineol, whereas the roots yielded nerolidol and an unidentified sesquiterpene. In contrast, leaves and roots of A. nuda were quite similar with the exception of the occurrence of estragole and anethole in roots only and not in the leaves. This partially explains the reported anise flavor of the edible roots of this species. The main compound of both roots and leaves of A. nuda was butan-2-yl (2Z)-3-(methylsulfanyl) prop-2-enoate, a new trans-β-methylthioacrylate derivative. This α, β-unsaturated methylsulfanyl ester, colloquially named (−)-nudaic ester, was characterized and assigned using 2D-NMR spectroscopy. The pronounced chemical differences between the examined species require further chemosystematic studies and the differences between roots, leaves and fruits may reflect the distinct vegetative (winter) and reproductive (summer) growth phases in these summer-deciduous plants.

A GC–MS untargeted metabolomics approach for the classification of chemical differences in grape juices based on fungal pathogen

Fungal bunch rot of grapes leads to production of detrimental flavour compounds, some of which are well characterised but others remain unidentified. The current study uses an untargeted metabolomics approach to classify volatile profiles of grape juices based on the presence of different fungal pathogens. Individual grape berries were inoculated with Botrytis cinerea, Penicillium expansum, Aspergillus niger or A. carbonarius. Grape bunches were inoculated and blended with healthy fruit, to provide 10% (w/w) infected juice. Juices from the above sample batches were analysed by GC/MS. PLS-DA of the normalised summed mass ions indicated sample classification according to pathogen. Compounds identified from those mass ion matrices that had high discriminative value for classification included 1,5-dimethylnaphthalene and several unidentified sesquiterpenes that were relatively higher in B. cinerea infected samples. A. niger and A. carbonarius samples were relatively higher in 2-(4-hexyl-2,5-dioxo-2,5-dihydrofuran-3-yl)acetic acid, while P. expansum samples were higher in γ-nonalactone and m-cresol.

Electrophysiological and Oviposition Responses of Tuta absoluta Females to Herbivore-Induced Volatiles in Tomato Plants.

In response to attack by herbivorous insects, plants produce semiochemicals for intra- and interspecific communication. The perception of these semiochemicals by conspecifics of the herbivore defines their choice for oviposition and feeding. We aimed to investigate the role of herbivore-induced plant volatiles (HIPVs) by Tuta absoluta larvae on the oviposition choice of conspecific females on tomato plants. We performed two- choice and non-choice bioassays with plants damaged by larvae feeding and intact control plants. We also collected headspace volatiles of those plants and tested the response of female antennae on those blends with Gas Chromatography- Electro-Antennographical Detection (GC-EAD). In total 55 compounds were collected from the headspace of T. absoluta larvae-infested plants. Our results show that female moths preferred to oviposit on intact control plants instead of damaged ones. Herbivory induced the emission of hexanal, (Ζ)-3-hexen-1-ol, (E)-β-ocimene, linalool, (Z)-3-hexenyl butanoate, methyl salicylate, indole, nerolidol, guaidiene-6,9, β-pinene, β-myrcene, α-terpinene, hexenyl hexanoate, β-elemene, β-caryophyllene and (Ε-Ε)- 4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT), one unidentified sesquiterpene and three unknown compounds. In Electroantennographic (EAG) assays, the antennae of T. absoluta females responded to hexanal, (Ζ)-3-hexen-1-ol, methyl salicylate and indole. The antennae of T. absoluta females exhibited a dose-response in EAG studies with authentic samples. Strong EAG responses were obtained for compounds induced on damaged tomato plants, as well as in nonanal, a compound emitted by both infested and control plants. These compounds could be utilized in integrated pest management of T. absoluta.

Behavioural and electrophysiological responses ofTriatoma dimidiata nymphs to conspecific faecal volatiles.

The behavioural and electrophysiological (electroantennography) responses of the first two instars of Triatoma dimidiata (Hemiptera: Reduviidae) Latreille to fresh and dry faecal headspace volatile extracts from fifth instar conspecific nymphs and synthetic compounds were analysed in this study. Recently emerged nymphs (3-5 days) aggregated around filter paper impregnated with dry faeces and around filter paper impregnated with extracts from both fresh and dry faeces. Older first instars (10-15 days) and second instars aggregated around filter paper impregnated with fresh and dry faeces, and their respective headspace extracts. Dry faecal volatile extracts elicited the strongest antennal responses, followed by fresh faecal extracts. Gas chromatography-mass spectrometry analysis of dried faecal headspace volatiles demonstrated the presence of 12 compounds: 2-ethyl-1-hexanol, 1,2,4-trimethylbenzene, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-tricosane, n-pentaeicosane, n-hexaeicosane, n-octaeicosane, nonanal, and 4-methyl quinazoline. In fresh faecal headspace extracts, only nonanal was clearly detected, although there were other trace compounds, including several unidentified sesquiterpenes. Four of the 11 compounds tested individually elicited aggregation behaviour at concentrations of 100 ng/µL and 1 µg/µL. A blend containing these four components also mediated the aggregation of nymphs. These volatiles may be valuable for developing monitoring methods and designing sensitive strategies to detect and measure T. dimidiata infestation.

Essential Oil Composition of Two Sphagnum Species Grown in Portugal and their In Vitro Culture Establishment

Two peat moss species, frequent both in the mainland Portugal and in the Azores archipelago, were evaluated for essential oil composition and establishment under in vitro culture. Sphagnum auriculatum and Sphagnum subnitens essential oils were isolated by hydrodistillation and analysed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). The essential oil of S. auriculatum was dominated by an as yet unidentified sesquiterpene, whereas zierene was the main component of S. subnitens essential oil. The in vitro cultures were successfully established for future studies of their chemical profile. The components present in essential oils obtained from S. auriculatum and S. subnitens together with morphological traits could be used to support the taxonomy of this plant group.

Apple Proliferation Phytoplasma Influences the Pattern of Plant Volatiles Emitted Depending on Pathogen Virulence

Apple proliferation (AP) and pear decline (PD) are the most severe diseases in pome fruit growing areas. AP-infected trees show typical symptoms such as witches’ broom, enlarged stipules, tasteless and dwarf fruits. PD-infected pears show a progressive weakening, reduced terminal growth, smaller fruits and die within weeks (quick decline) or years (slow decline). The diseases are caused by the cell-wall lacking bacteria Candidatus Phytoplasma mali (AP phytoplasma) and Ca. P. pyri (PD phytoplasma), respectively. In previous studies it has been shown that AP-infected apple trees emitted higher amounts of the sesquiterpene β-caryophyllene, an attractant of the insect vector Cacopsylla picta (Hemiptera: Psyllidae), thereby facilitating the dispersal of AP phytoplasma. In the present study, volatile organic compounds (VOCs) occurring in the headspace of plants infected with Ca. P. mali strains causing different severity of symptoms in apple plants were collected, analyzed and identified. Headspace samples from healthy and AP-infected model plant tobacco (Nicotiana occidentalis) and apple (Malus domestica) as well as from healthy and PD-infected pear (Pyrus communis) were investigated via thermodesorption and GC-MS analysis. Significantly higher concentrations of ethyl benzoate were produced in all phytoplasma-infected plants compared to healthy ones and an as yet unidentified sesquiterpene differed between the odor bouquets of healthy and by Ca. P. mali infected tobacco plants. Additionally, statistically significant higher amounts of both compounds were measured in the headspace of plants infected by the virulent AP strain. In apple, significantly higher concentrations of ethyl benzoate and methyl salicylate were observed for trees infected with strains of Ca. P. mali. Ethyl benzoate was also detected in the headspace of pear trees infected with Ca. P. pyri.

Plant response to touch affects the behaviour of aphids and ladybirds

Touching between leaves of the same plant and/or by neighbouring plants is one of the most common mechanical stimuli to which an individual plant has to respond on a daily basis. The possible ecological implications of a plant’s response to touch on plant–insect interactions have not been explicitly investigated. We examined whether plant response to 1 min daily touching over a period of 6 days affects host plant acceptance by the bird cherry-oat aphid Rhopalosiphum padi L. on maize and by the black bean aphid Aphis fabae Scop. on bean, as well as olfactory preference of an aphid predator, seven-spotted ladybird Coccinella septempunctata L. Maize plants responded to touch with significant reduction in plant height, total plant biomass, leaf weight, leaf surface, shoot/root ratio and specific leaf area (SLA), while bean plants responded with reduced stem height and reduced SLA. Both aphid species showed significantly reduced acceptance of touched plants compared with untouched plants. The two aphid species and male and female ladybirds preferred volatiles from untouched plants over those from touched plants. Volatiles in the headspace of touched and untouched plants were collected and identified. Stepwise discriminant analyses identified (E)-nerolidol and (E)-β-caryophyllene in maize and 6-methyl-5-hepten-2-one and an unidentified sesquiterpene in bean as the best discriminating compounds in the volatile profiles of touched plants. Our study suggests that touch-induced changes in plants can potentially affect host plant selection by aphids and habitat searching by ladybirds. Thus, touch-induced changes in plants may have significant effects at higher trophic levels.

Sesquiterpene lactones. XXIII. Isolation of sesquiterpene lactones from Centaurea L. species

Sesquiterpene lactones were isolated from 18 species or subspecies of the genus <em>Centaurea L.</em>: salonitenolide (I) was found in <em>C. crithmifolia Vis., C. friderici Vis., C, paniculata L., C. calcitrapa L., C. pontica </em>Prodan et E. L' Nyarady, <em>C. eriophora L., C. alba L. subsp. deusta</em> (Ten.) Nyman, <em>C. alba L.</em> subsp. <em>caliacrae</em> (Prodan) Dostal and <em>C. weldeniana</em> Reichenb.; cnicin (II) was found in: <em>C. vallesiaca (DC)</em>. Jordan, <em>C. calcitrapa L., C. aspera L.</em> subsp. <em>aspera, C. sphaerocephala L.</em> subsp. <em>lusitanica</em> (Boiss. et Reuter) Nyman, <em>C. sulphurea</em> Willd., <em>C. eriophora L.</em> and <em>C. rocheliana</em> (Heuffel) Dostal; cynaropicrin (III) was detected in <em>C. debeauxii</em> Gren. et Gordon subsp. <em>thuillieri</em> Dostal; acroptillin (V), repin (VI) and janerin (VII) in <em>C. bella</em> Trautv. Other unidentified sesquiterpene lactones were also found to be present in the examined plants.

Comparative analysis of α- and β-thujone in the essential oil and supercritical CO2 extract of sage (Salvia officinalis L.)

Salvia officinalis L. (Sage) is an important industrial plant used both for food and pharmaceutical purposes. The terpene fraction of this plant, which contains thujones and other mono and sesquiterpenoids, is responsible for many of its therapeutic and culinary properties. We used two extraction methods [hydrodistillation (HD) to obtain the essential oil (EO), and supercritical CO2 extraction (SFE)] to analyze by gas chromatography–mass spectrometry (GC–MS) the terpene fraction extracted from sage dried leaves. α-Thujone, β-thujone and other oxygenated monoterpenes (1,8-cineole, linalool, camphor, borneol and bornyl acetate) as well as hydrocarbon (β-caryophyllene and α-humulene) and oxygenated sesquiterpenes (caryophyllene oxide, viridiflorol, humulene epoxide II and III) were found. The EO contained a significantly (p < 0.05) higher percentage of 1,8-cineole (10.4%), α-thujone (17.3%) and camphor (29.2%), whereas supercritical fluid (SF) extracts contained a significantly higher percentage of borneol (8.4%), bornyl acetate (2.2%), α-humulene (6.4%), viridiflorol (22.1%), humulene epoxide II and III (2.4% and 0.4%), and some unidentified sesquiterpene alcohols. Both EO and SF extracts contained equal amounts of β-thujone (4.8%) and β-caryophyllene (~7%). Our results show that HD of EO is a more efficient and economic method for α- and β-thujone extraction.

Temporal development of sesquiterpene hydrocarbon profiles of different grape varieties during ripening

ABSTRACTTo investigate the profiles of sesquiterpene hydrocarbons in grape berries at different developmental stages several cultivars of Vitis vinifera (Gewürztraminer, Riesling, Yellow Muscat, Shiraz, Lemberger, Cabernet Sauvignon) were analysed during ripening. Therefore, HS‐SPME‐GC‐MS measurements were performed with intact grape berries. The measurements demonstrated that grapes emit numerous sesquiterpene hydrocarbons and that the sesquiterpene profile exhibits a characteristic profile, depending on the variety and the developmental stage. In particular, bicylic sesquiterpenes with a cadinane backbone increased during ripening, while acyclic sesquiterpenes such as (E,E)‐α‐farnesene decreased, except for Gewürztraminer which shows increasing amounts of acyclic sesquiterpenes towards harvest. Furthermore, the profiles of the emitted sesquiterpenes differed significantly. In particular, Gewürztraminer possessed remarkably high amounts of (E,E)‐α‐farnesene, (3E,6Z)‐α‐farnesene and (E,E)‐methylfarnesoate, while the sesquiterpene profiles of Riesling, Lemberger, Shiraz and Yellow Muscat were dominated by bi‐ and polycyclic sesquiterpenes. Cabernet Sauvignon showed only minor profile changes during ripening and its comparatively low sesquiterpene hydrocarbon amounts were dominated by (E)‐β‐caryophyllene, α‐humulene and an unidentified sesquiterpene. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Efficacy of fatty acids and terpenoids and weakness of electronic nose response as tracers of Asiago d’Allevo PDO cheese produced in different seasons

The goal of this study was to verify the suitability of using fatty acids (FAs), terpenoids, and electronic nose response as potential tracers of the seasonal variations in Asiago d’Allevo PDO cheese. Cheese samples produced during the early and late summer grazing and the autumn/winter indoor seasons were compared. Based on their FA composition, the early and late summer cheeses were almost completely indistinguishable from each other. However, they both demonstrated higher quality when compared to the autumn/winter cheeses, showing lower levels of hypercholesterolemic saturated FAs (C12, C14, and C16) and higher levels of total mono- and polyunsaturated FAs, oleic (C18:1 c9), trans-vaccenic (C18:1 t11), rumenic (C18:2 c9t11), and α-linolenic (C18:3 c9c12c15) acids. Among terpenoids, camphene, cedrane, and total sesquiterpenoids were able to differentiate the cheeses manufactured during the three periods of production. Moreover, α-pinene, α-thujene, β-pinene, δ-3-carene, myrtenol, dihydrocarveol isomer 1, and unidentified sesquiterpene 1 distinguished the late summer cheeses from those obtained in the other two seasons. Principal component analysis of electronic nose data showed that the Asiago cheese samples were widely dispersed in the score plot and no clear clusters appeared evident. Furthermore, cross-validated linear discriminant analysis of the electronic nose data showed unsatisfactory classification performance (53.8%) regarding the period of production. Our results showed that coupling FAs and terpenoids information could be a suitable method for tracing Asiago d’Allevo PDO cheeses according to their season of production. However, no reliable information at this level seemed to be obtainable from the electronic nose response.

Floral scent emissions from Asarum yaeyamense and related species

The flowers of Asarum are usually regarded as scentless or sometimes to have a foul odor. Recently, we noticed that Asarum yaeyamense, endemic to Iriomote Island, Japan, has a floral fragrance with a distinct “fruity note.” To determine the chemical characteristics of this fragrance and whether “non-scented” Asarum species emit any volatiles, we collected floral scents of A. yaeyamense and related species ( A. lutchuense, A. hypogynum, A. fudsinoi, A dissitum, A. tokarense, and A. senkakuinsulare) using headspace methods and analyzed these scents by gas chromatography–mass spectrometry (GC–MS). The results indicated that A. yaeyamense mainly emitted α-cedrene (tentatively identified), an unidentified sesquiterpene, methyl tiglate, and manoyl oxide (tentatively identified). Methyl tiglate may be a source of the “fruity note” in the A. yaeyamense fragrance. We also detected emissions of volatiles, mainly sesquiterpenes, from some “non-scented” Asarum species. This study constitutes a rare case of the detection of the emission of a diterpene (manoyl oxide) as a floral scent volatile.

A Preliminary Investigation of the Leaf Essential Oils of the Australian Species of Endressia, Steganthera and Wilkiea (Monimiaceae)

The leaf oils of the 19 Australian species of Endressia, Steganthera and Wilkiea within the family Monimiaceae have been examined by GC and GC/MS. All produced oils in poor yields that were dominated by sesquiterpenes. Endressia wardellii gave a leaf oil in which α-humulene (14–17%) and bicyclogermacrene (17–24%) were the main components. The leaf oil of Steganthera australiana was almost entirely sesquiterpenoid with no one single compound predominating. Steganthera cooperorum, from two disjunct population centers produced different oils indicating significant chemical divergence. In plants from Topaz and Wooroonooran National Park the major components identified were aromadendrene (6–10%), viridiflorene (7–8%), globulol (7–9%) and b-eudesmol (8–11%); dodecanal (2–4%) was also present. However, material from North Mary Logging Area and Daintree National Park produced an oil dominated by elemol (30–42%) and hedycaryol (approx. 8%). These compounds were accompanied by α-, β- and γ-eudesmol (10–14%, 10–14%, 5–9%, respectively). Steganthera hirsuta produced a sesquiterpenoid oil in which the principal components were bicyclogermacrene (37–56%), β-caryophyllene (2–17%) and germacrene D (2–22%). The principal component of Steganthera laxiflora subsp. laxiflora was viridiflorene (13–20%). Steganthera macooraia gave a leaf oil in which the principle sesquiterpenes identified were guaiol (2–23%), bulnesol (0.7–10%) and elemol (10–22%). Steganthera laxiflora subsp. lewisensis gave an oil in which viridiflorene (11.8%) was the principal, with 2-dodecenal (6.3%) also present. The leaf oil of Wilkiea angustifolia was dominated by sesquiterpenes, with β-eudesmol (35%) being the principal component, while in Wilkiea austroqueenslandica the principal components were (E)- β-ocimene (5–9%), germacrene D (7–18%) and bicyclogermacrene (23–26%). Wilkiea cordata gave a variable oil, with either β-eudesmol (22–25%) or spathulenol (11.3%), and several unidentified sesquiterpenes as major components. Wilkiea huegeliana produced an oil in which the main components were α-pinene (10–12%) and viridiflorene (4–9%). Wilkiea longipes gave an oil in which monoterpenes accounted for up to 20% of the oil. In this species, the major monoterpene was (Z)-β-ocimene (11–15%). The remainder of the oil was composed of sesquiterpenes with no one compound predominating. Wilkiea macrophylla was unusual amongst these species in that its oil contained significant amounts of aliphatic aldehydes, in this case dodecanal (2–35%) and (2)-dodecenal (0.1–2%), with β-caryophyllene (14–24%) as the major sesquiterpene. In Wilkiea pubescens the leaf oil was dominated by sesquiterpenes, with no one compound dominating the oil. The aliphatic aldehyde, dodecanal (4–5%) was also present. The leaf oil of Wilkiea rigidifolia contained (Z)-β-ocimene (3.4–11.5%), bicyclogermacrene (3.2–17.4%) and germacrene B (0.3–14.5%) as major components. Wilkiea smithii produced a complicated oil in which β-caryophyllene (10.4%), bicyclogermacrene (9.6%), caryophyllene oxide (8.9%) and spathulenol (16.7%) were the principal components. Wilkiea sp. (McDowall Range J.G.Tracey 14552) yielded a complicated oil that was entirely sesquiterpenoid in nature. The principal components were selina-6-en-4-ol (30.7%) and germacrene D-4-ol (18.6%). Wilkiea sp. (Palmerston B.P.Hyland 80) gave an entirely sesquiterpenoid oil with spathulenol (22%) as the principal component, while Wilkiea sp. (Russell Gorge S.J.Dansie 1909) produced a complicated sesquiterpenic oil with elemol (19.2%) as principal component.